Re: Bugs in TOAST handling, OID assignment and redo recovery

On Wed, Apr 18, 2018 at 12:07:52PM +0530, Pavan Deolasee wrote:
> 
> 
> On Thu, Apr 12, 2018 at 5:53 AM, Peter Eisentraut <
> peter.eisentraut@2ndquadrant.com> wrote:
> 
>     On 4/10/18 06:29, Pavan Deolasee wrote:
>     > One of our 2ndQuadrant support customers recently reported a sudden rush
>     > of TOAST errors post a crash recovery, nearly causing an outage. Most
>     > errors read like this:
>     >
>     > ERROR: unexpected chunk number 0 (expected 1) for toast value nnnn
> 
>     While researching this, I found that the terminology in this code is
>     quite inconsistent.  It talks about chunks ids, chunk indexes, chunk
>     numbers, etc. seemingly interchangeably.  The above error is actually
>     about the chunk_seq, not about the chunk_id, as one might think.
> 
>     The attached patch is my attempt to clean this up a bit.  Thoughts?
> 
> 
> While I agree that we should clean it up, I wonder if changing error text would
> be a good idea. These errors are being reported by a very long time and if we
> change the text, we might forget the knowledge about the past reports.
> 
> Also, "toast value" is same as "chunk_id". Should we clean up something there
> too? "chunk_seq number" -- should that be just "chunk_seq"?

We can put a comment next to the error message C string if we want to
keep historical knowledge.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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